<script>
	let age = 46;
	
	if(age< 18){
		document.write("小屁孩儿");
	}else if(age < 28){
		document.write("小年轻")
	}else if(age < 48){
		document.write("老黄牛")
	}else if(age < 68){
		document.write("不是老人变坏了，而是坏人变老了")
	}else{
		document.write("say good byd");
	}
</script>